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Phosphate Glasses

Definition: certain glasses from which certain optical fibers and laser gain media can be made, for example

German: Phosphatgläser

Categories: fiber optics and waveguides, optical materials

How to cite the article; suggest additional literature

Phosphate glasses are glass materials based on phosphorus pentoxide (P2O5), usually with some added chemical components. They are used as laser gain media – both in bulk lasers and in the form of optical fibers. One of their primary advantages is their very high solubility for rare earth ions (→ rare-earth-doped gain media) such as erbium (Er3+), ytterbium (Yb3+) and neodymium (Nd3+). This means that high concentrations of laser-active rare earth ions can be incorporated into phosphate glasses without detrimental effects such as clustering, which could degrade the performance via quenching effects. For example, erbium-doped fibers can be made with much higher doping concentrations than silica fibers: several weight percent are possible. This allows the construction of rather short fiber lasers and amplifiers, which can be beneficial not only for reasons of compactness:

Some other characteristics of phosphate glasses:

Mixtures of phosphate and fluoride glass are called fluorophosphate glasses. Similarly, there are phosphosilicate and aluminophosphate glasses. Such glasses are also often used as laser gain media.

The combination of phosphate and silica fibers in a device can be problematic, since fusion splicing of these different materials is difficult (although not impossible) due to the very different glass transition temperatures.


 [1]E. Snitzer et al., “Phosphate glass Er3+ laser”, IEEE J. Quantum Electron. 4 (5), 360 (1968)
[2]V. B. Kravchenko and Yu. P. Rudnitskii, “Phosphate laser glasses”, Sov. J. Quantum Electron. 9 (4), 399 (1979)
[3]L. Yan and C. H. Lee, “Thermal effects in end-pumped Nd:phosphate glasses”, J. Appl. Phys. 75 (3), 1286 (1994)
 [4]Y. W. Lee et al., “20 W single-mode Yb3+-doped phosphate fiber laser”, Opt. Lett. 31 (22), 3255 (2006)
[5]A. Schulzgen et al., “Microstructured active phosphate glass fibers for fiber lasers”, IEEE J. Lightwave Technol. 27 (11), 1734 (2009)
 [6]S. Xu et al., “400 mW ultrashort cavity low-noise single-frequency Yb3+-doped phosphate fiber laser”, Opt. Lett. 36 (18), 3708 (2011)
[7]G. Zhang et al., “Neodymium-doped phosphate fiber lasers with an all-solid microstructured inner cladding”, Opt. Lett. 37 (12), 2259 (2012)

(Suggest additional literature!)

See also: fibers, silica fibers, fiber lasers, fiber amplifiers, gain media, doping concentration
and other articles in the categories fiber optics and waveguides, optical materials

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